Examines the extreme form of market leadership known as market share dominance. Firstly, cites the advantages of market leadership and then goes on to discuss the case of market share dominance in the Thai imported Scotch whisky market, providing a detailed comparison of the marketing mix of the leader and challenger. Next reports the results of four market research studies by ACNielsen in Thailand over the same nine-year period which examined consumer attitudes and image patterns among male whisky-drinkers. Ascribes consumers' behavioural loyalty to a market leader to double jeopardy - the disadvantage suffered by the challenger as a result of lower market share, and therefore fewer customers, together with the tendency of the leader's loyal consumers to buy more frequently. Ends by proposing an alternative approach which includes a market share threshold beyond which brand dominance becomes deeply embedded and therefore much more difficult to dislodge.